Wedge apparatus for use in operating on a bone

ABSTRACT

The relationship between first and second portions of a bone in a patient&#39;s body is changed by moving a wedge member into a slot formed in the bone. Force is applied against hard cortical bone by the wedge member. This force pivots the first portion of the bone relative to the second portion of the bone about an axis extending through bone interconnecting the first and second portions of the bone. As the wedge member moves into the bone, a side surface of the wedge member is moved into alignment with an outer side surface of the bone. The wedge member is fixedly connected with the bone. The wedge member is rigid so that the bone can immediately be load bearing. One or more openings may be provided in the wedge member to enable bone to grow through the wedge member. The wedge member may contain a material which promotes growth of bone through the wedge member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending U.S. patent applicationSer. No. 10/438,705, filed May 15, 2003, which in turn is a continuationof application Ser. No. 09/566,070, filed May 5, 2000 now U.S. Pat. No.6,575,982, which in turn is a continuation of application Ser. No.09/109,126, filed Jun. 30, 1998, now U.S. Pat. No. 6,086,593.

BACKGROUND OF THE INVENTION

The present invention relates to a new and improved method and apparatusin which a wedge member is used to change a spatial relationship betweenportions of bone in a patient's body.

A known method for performing an osteotomy includes forming a slot whichextends part way through a bone. A forked wedge tool is inserted intothe slot. A plate is then placed in a central opening in the forkedwedge tool and positioned against the so bone. The plate is secured tothe bone. The forked wedge tool is then removed from the opening. Thismethod of performing an osteotomy is disclosed in U.S. Pat. No.5,620,448.

The foregoing osteotomy changes the spatial relationship betweenportions of a bone in a patient's body by forming and maintaining awedge-shape opening in the bone. In other known methods, the spatialrelationship between portions of a bone in a patient's body has beenchanged by removing a wedge-shape piece from the bone. The resultingopening is closed to effect the relative movement between portions ofthe bone. The performance of an osteotomy which includes removing awedge-shaped piece of bone is disclosed in U.S. Pat. Nos. 5,053,039 and5,601,565

SUMMARY OF THE INVENTION

The present invention relates to a new and improved method and apparatusfor use in changing a spatial relationship between portions of a bone ina patient's body. When this is to be done, an opening is formed in aportion of the patient's body tissue to at least partially expose thebone. Force is applied to the bone with a wedge member to move oneportion of the bone relative to another portion of the bone. The wedgemember may be fixedly connected with either or both portions of thebone. The opening in the patient's body is then closed with the wedgemember disposed in engagement with the bone. Force can be transmittedbetween portions of the bone through the wedge member.

The wedge member may taper from a thick edge to a thin edge and have aside surface which extends from one end of the thin edge, along thethick edge, to the opposite end of the thin edge. The side surface ofthe wedge member may have a cross sectional configuration correspondingto the configuration of a portion of an outer side surface of the bone.This enables the wedge member to be aligned with the outer side surfaceof the bone.

The wedge member may be positioned relative to the bone at a locationwhere a layer of hard cortical bone encloses soft cancellous bone.Opposite ends of the thin leading edge of the wedge member may bepositioned in engagement with the hard cortical bone while a centralportion of the thin edge of the wedge member engages the soft cancellousbone. In addition, the layer of hard cortical bone may engage the wedgemember adjacent to the side surface of the wedge member.

It is contemplated that the wedge member may have many differentconstructions. It is believed that it will be advantageous to form thewedge member with one or more openings through which bone can grow. Thewedge member may be coated with and/or contain bone growth promotingmaterial. The wedge member may be hollow and contain material whichpromotes growth of bone through the wedge member.

A screw member may extend ahead of the thin leading edge of the wedgemember and engage hard cortical bone. Force may be transmitted from thescrew member to the wedge member to move the wedge member relative tothe bone. Alternatively, the wedge member may have a circular crosssectional configuration with an external thread convolution to enablethe wedge member to be moved into an opening in a bone by rotating thewedge member.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomemore apparent upon a consideration of the following description taken inconnection with the accompanying drawings wherein.

FIG. 1 is a schematic posterior illustration of the relationship betweenbones in a patient's body;

FIG. 2 is a schematic illustration, generally similar to FIG. 1,illustrating the manner in which a wedge member is utilized to change aspatial relationship between portions of one of the bones of FIG. 1;

FIG. 3 is an enlarged plan view, taken generally along the line 3-3 ofFIG. 2, illustrating the configuration of the wedge member;

FIG. 4 is a side elevational view, taken generally along the line 4-4 ofFIG. 3, further illustrating the configuration of the wedge member;

FIG. 5 is an enlarged schematic fragmentary sectional view of a portionof one of the bones of FIG. 2 and illustrating the relationship of thewedge member to the bone;

FIG. 6 is a plan view, taken generally along the line 6-6 of FIG. 5,further illustrating the relationship of the wedge member to the bone;

FIG. 7 is a schematic fragmentary sectional view, generally similar toFIG. 5, illustrating the relationship of a second embodiment of thewedge member to the bone;

FIG. 8 is a plan view, taken generally along the line 8-8 of FIG. 7,further illustrating the relationship of the wedge member to the bone;

FIG. 9 is a schematic pictorial illustration depicting the constructionof a screw which forms another embodiment of the wedge member;

FIG. 10 is an enlarged sectional view of an embodiment of the wedgemember of FIGS. 3-6 which is hollow and contains material to promotebone growth through the wedge member;

FIG. 11 is a fragmentary schematic sectional view, generally similar toFIG. 5, illustrating the relationship of another embodiment of the wedgemember to the bone;

FIG. 12 is a plan view, taken generally along the line 12-12 of FIG. 11and illustrating the configuration of an opening extending through thewedge member of FIG. 11;

FIG. 13 is a schematic fragmentary sectional view, similar to FIGS. 5, 7and 11, illustrating the relationship of a stepped wedge member to abone; and

FIG. 14 is a plan view, taken generally along the line 14-14 of FIG. 13,further illustrating the configuration of the stepped wedge member.

DESCRIPTION OF SPECIFIC PREFERRED EMBODIMENTS OF THE INVENTION

General Description

FIGS. 1 and 2 are schematic posterior illustrations of bones in a leg 20of a patient. A tibia bone 22 and fibula bone 24 support a femur bone26. Although bones 22, 24 and 26 in a leg of a patient have beenillustrated in FIGS. 1 and 2, it should be understood that the methodand apparatus of the present invention may be used in association withbones in many different portions of a patient's body.

In FIG. 1, the upper end portion 30 of the tibia bone 22 is angularlymisaligned with the lower portion 32 of the tibia bone. Thus, in FIG. 1,the upper end portion 30 of the tibia bone 22 is offset in acounterclockwise direction by approximately 7 degrees from a desiredorientation relative to the lower portion 32 of the tibia bone 22. Inaccordance with a feature of the present invention, a wedge member 36(FIGS. 2, 3 and 4) is utilized to change the spatial relationship of theupper end portion 30 of the tibia bone 22 relative to the lower portion32 of the tibia bone.

The wedge member 36 is formed of a relatively hard rigid material. Thewedge member 36 is capable of transmitting force between the upper endportion 30 and the lower portion 32 of the tibia bone 22. This enablesthe leg 20 of the patient to be weight bearing as soon as the wedgemember 36 is positioned in the tibia bone 22. Thereafter, bone may growthrough the wedge member 36 between the upper end portion 30 and lowerportion 32 of the tibia bone 22.

When the wedge member 36 is to be utilized to change the spatialrelationship of the upper end portion 30 (FIG. 2) of the tibia bone 22relative to the lower portion 32 of the tibia bone, an opening is formedin the fleshy part of the body tissue in the leg of the patient toexpose the portion of the tibia bone where the wedge member is to beinstalled. It is contemplated that it may be preferred to install thewedge member 36 approximately two to three millimeters below the upperend of the tibia bone. The specific location where the wedge member 36is installed will depend upon the surgeon's judgment. It is contemplatedthat the wedge member 36 may be installed at any one of many locationsrelative to a particular bone.

A saw cut is made to form a slot at the location where the wedge member36 is to be installed. The saw cut and resulting slot extend only partway through the tibia bone 22. This results in the upper end portion 30of the tibia bone 22 being connected with the lower portion 32 of thetibia bone by a connector or hinge portion 40 (FIG. 2) of the tibiabone.

Once a slot has been formed between the upper end portion 30 and lowerportion 32 of the tibia bone, the wedge member 36 is moved into theslot. A thin edge 44 (FIGS. 3 and 4) of the wedge member 36 is leadingand a thick edge 46 of the wedge member trailing as the wedge membermoves into the slot. As the wedge member 36 is forced into the slotbetween the upper end portion 30 and lower portion 32 of the tibia bone22 (FIG. 2), the wedge member pivots the upper end portion of the tibiabone in a clockwise direction (as viewed in FIG. 2) relative to thelower portion of the tibia bone about an axis extending through theconnector or hinge portion 40.

The wedge member 36 has an outer side surface 50 (FIGS. 3 and 4) whichextends from one end 52 (FIG. 3) of the thin edge 44 of the wedge member36 along the thick edge 46 of the wedge member to the opposite end 54 ofthe thin edge 44. The outer side surface 50 of the wedge member 36 hasthe same configuration as the outer side surface of the tibia bone 22 atthe location where the saw cut formed the slot between the upper endportion 30 and lower portion 32 of the tibia bone. The outer sidesurface 50 of the wedge member may be formed in a plurality of sections.

Although the outer side surface 50 of the wedge member 36 has beenillustrated schematically in FIG. 3 as forming a portion of a circle, itshould be understood that the outer side surface 50 of the wedge member36 will probably not have a configuration which corresponds to theconfiguration of a portion of a circle. The configuration of the outerside surface 50 of the wedge member 36 conforms to the cross sectionalconfiguration of the outside surface of the bone 22 at the locationwhere the wedge member is to be installed in the bone.

Since the outer side surface 50 of the wedge member 36 has aconfiguration corresponding to the configuration of the outer sidesurface of the bone 22 at the location where the wedge member is to beinstalled in the tibia bone (FIG. 2), the outer side surface 50 (FIG. 3)of the wedge member can be moved into alignment with the outer sidesurface of the bone 22. This enables a hard cortical outer layer of thebone 22 to engage opposite major sides of the wedge member 36 adjacentto the outer side surface 50 of the wedge member. The outer layer ofhard cortical bone has continuous engagement with the wedge member 36from the thin edge 44 to the thick edge 46 of the wedge member. Thismaximizes the extent of engagement of the hard outer layer of corticalbone with the wedge member 36 to avoid stress concentrations in the hardcortical outer layer.

If the wedge member 36 did not have an outer side surface 50 whichextended along the outer side surface of the bone 22 from opposite sidesof the hinge portion 40 of the bone, the hard cortical outer layer ofbone would only be partially supported by the wedge member 36 at theslot in the bone. This would result in the load which is transmittedbetween the upper end portion 30 of the bone 22 and the lower portion 32of the bone being concentrated at a relatively small area on the hardcortical outer layer of bone at the opening to the slot.

Once the wedge member 36 has been positioned relative to the bone 22, inthe manner illustrated in FIG. 2, the wedge member is fixedly connectedwith the bone. In the illustrated embodiment of the invention, suitablescrews 58 (FIG. 2) are used to fixedly connect mounting strips 60, 62and 64 (FIG. 3) with the upper end portion 30 and lower portion 32 ofthe tibia bone 22. The mounting strips 60, 62 and 64 and screws 58 holdthe wedge member 36 against movement relative to the bone 22 duringsubsequent loading of the bone by the patient.

The opening in the fleshy portion of the leg of the patient is thenclosed. Since the wedge member 36 has a rigid structure, the leg 20 ofthe patient can be load bearing immediately after closing of the openingwhich exposed the bone 22. With she passage of time, bone grows throughthe wedge member 36 between the upper end portion 30 and lower portion32 of the bone 22.

Wedge Member

The wedge member 36 (FIGS. 3 and 4) has upper and lower major sidesurfaces 68 and 70 (FIG. 4). The upper and lower major side surfaces 68and 70 slope toward each other from the thick edge 46 to the thin edge44 of the wedge member 36. It is contemplated that a plurality of wedgemembers 36 having different acute angles between upper and lower majorside surfaces 68 and 70 may be provided. This enables a surgeon toselect a wedge member 36 having a desired thickness at the thick edge46.

The acute angle between the flat upper and lower major side surfaces 68and 70 is determined by the extent to which the spatial relationshipbetween the upper end portion 30 and the lower portion 32 (FIGS. 1 and2) of the bone 22 is to be changed by insertion of the wedge member 36.Of course, the larger the bone with which the wedge member 36 is used,the smaller is the angle between the upper and lower major side surfaces66 and 68 to obtain a desired thickness of the wedge member at the thickedge 46 of the wedge member.

It is believed that it may be desired to have the angle between theupper and lower major side surfaces 68 and 70 be within a range betweenone degree and twenty degrees. Although the specific angle providedbetween the upper and lower major side surfaces 68 and 70 will dependupon the environment in which the wedge member is to be utilized, it isbelieved that the angle between the upper and lower major side surfaces68 and 70 may frequently be between two degrees and ten degrees. Itshould be understood that the foregoing specific ranges of sizes for theangle between the upper and lower major side surfaces 68 and 70 havebeen set forth herein for purposes of clarity of description and it iscontemplated that the angle between the upper and lower major sidesurfaces may be any one of many angles other than these specific angles.

The wedge member 36 may be formed of any one of many different knownmaterials which are compatible with a patient's body. For example, thewedge member may be formed of human or animal bone, stainless steel,tantalum, a porous ceramic, or a polymeric material. If desired, thewedge member 36 may be formed of a biodegradable material. However, itis preferred to have the wedge member 36 formed of a rigid materialwhich is capable of enabling the leg 20 to be weight bearing immediatelyafter the wedge member 36 has been installed in the bone 22.

The wedge member 36 is porous so that bone can grow through the wedgemember. In the illustrated embodiment of the invention, the wedge member36 has a plurality of openings or passages 74 which extend through thewedge member between the upper and lower major side surfaces 68 and 70.The openings 74 enable bone to grow through the wedge member 36.

It is believed that it may be preferred to form the wedge member of anopen cell material to provide cavities in which bone can grow throughthe wedge member. The wedge member 36 may have a cellular constructionsimilar to coral. Alternatively, straight passages may be drilled orcast in the wedge member 36. It is contemplated that the wedge member 36may be coated with a material which promotes the growth of bone. If thewedge member 36 has a cellular construction, the cells may be at leastpartially filled with bone growth promoting material.

When the wedge member 36 is to be inserted into the bone 22 to changethe spatial relationship between the upper end portion 30 of the boneand the lower portion 32 of the bone, a location for insertion of thewedge member is selected by a surgeon. It is contemplated that it may bedesired to locate the wedge member 36 approximately two to fivemillimeters below the upper end of the tibia bone. However, the specificlocation at which the wedge member is inserted into the bone 22 will beselected by the surgeon as a function of the result desired from aparticular operation.

A saw slot is formed at the location where the wedge member is to beinserted into the bone. The slot extends only part way through the bone.Thus, in FIG. 2, the slot extended from the left side of the tibia bone22 toward the right side to a location which was spaced from the rightside of the tibia bone. This results in the upper end portion 30 andlower portion 32 of the bone 22 being interconnected by a connector orhinge portion 40 after the slot is formed. The thickness of the hingeportion 40 will depend upon the location where the wedge member is beinginstalled, the extent to which the spatial relationship between portionsof the bone are to be changed by insertion of the wedge member, and thephysical characteristics of the bone itself.

Once the slot has been formed, with a saw or other device at a desiredlocation in the bone, the wedge member 36 is moved into the slot. Thethin edge 44 of the wedge member is easily inserted into an entryopening to the slot. Force is then applied against the thick edge 46 ofthe wedge member to move the wedge member further into the slot.

When the thin edge 44 of the wedge member 36 is initially positioned inthe slot, the thin edge of the wedge member is diametrically oppositefrom the hinge portion 40 of the bone 22. A longitudinal axis of thethin edge 44, that is an axis extending between the opposite ends 52 and54 (FIG. 3) of the thin edge, is parallel to the bottom of the slot whenthe thin edge is initially positioned in the slot. At this time, an axisperpendicular to the thin edge 44 and extending through the center ofthe wedge member 36 is aligned with an axis extending perpendicular tothe bottom of inner edge of the slot and extending through the center ofthe bone 22.

The wedge member 36 is then moved into the slot along a linear pathwhich extends perpendicular to the bottom or inner end of the slot andto the thin edge 44 of the wedge member. As the wedge member 36 movesinto the slot along the linear path, the upper major side surface 68(FIGS. 4 and 5) of the wedge member slides along and applies forceagainst the upper end portion 30 of the tibia bone 22. As the wedgemember 36 moves into the slot along the linear path, the lower majorside surface 70 of the wedge member slides along and applies forceagainst the lower portion 32 of the tibia bone 22. The wedge member 36is moved into the slot under the influence of force applied against thetrailing thick edge portion 46.

Although it is contemplated that the wedge member 36 could be mounted atmany different locations in many different types of bone, the wedgemember 36 is illustrated in FIGS. 5 and 6 as being positioned in thetibia bone 22 at a location in which an outer layer 80 of hard corticalbone extends around a core 90 of soft cancellous bone.

As the thin leading edge 44 of the wedge member 36 moves into the slot,the central portion of the thin leading edge 44 engages the outer layer80 of hard cortical bone at the entry to the slot on a side of the bone22 opposite from the hinge or connector portion 40. Force is appliedagainst the outer layer 80 of hard cortical bone by the upper and lowermajor side surfaces 68 and 70 of the wedge member 36 at a locationadjacent to the center of the opening to the slot. The force appliedagainst the outer layer 80 of hard cortical bone by the thin leading endportion of the wedge member 36 initiates pivotal movement of the upperend portion 30 of the bone 22 about an axis extend through the hingeportion 40.

As the thin edge 44 of the wedge member moves further into the slot, thearea of engagement of the thin leading edge 44 of the wedge member withthe outer layer 80 of hard cortical bone moves outward from a centralportion of the thin leading edge 44 toward the opposite ends 52 and 54of the thin leading edge 44 (FIGS. 3 and 6). The upper and lower majorsides 68 and 70 of the wedge member move into engagement with the layer80 of hard cortical bone along opposite sides of the bone 22.

As the area of engagement of the thin leading edge 44 of the wedgemember 36 with the outer layer 80 of hard cortical bone moves toward theopposite ends of the thin edge 44, the central portion of the thin edge44 engages the core 90 of soft cancellous bone. When the central portionof the thin edge 44 of the wedge member 36 engages the core 90 of softcancellous bone, portions of the thin edge 44 on opposite sides of thecentral portion of the thin edge are in engagement with the outer layer80 of hard cortical bone. However, depending upon the thickness and/orconfiguration of the outer layer 80 of hard cortical bone, the centralportion of the thin edge 44 may or may not engage the core 90 of softcancellous bone before the opposite ends 52 and 54 of the thin edge 44of the wedge member 36 move into initial engagement with the outer layer80 of hard cortical bone.

Continued movement of the wedge member 36 toward the bottom of the slotin the bone 22, that is, toward the right as viewed in FIGS. 5 and 6,moves the entire thin leading edge 44 of the wedge member intoengagement with the core 90 of soft cancellous bone. As this occurs, thewedge member 36 moves into engagement with the outer layer 80 of hardcortical bone along opposite sides of the wedge member adjacent to theouter side surface 50 of the wedge member and adjacent to opposite sidesof the bone 22. Although the thin leading edge 44 of the wedge member isin engagement with the core 90 of soft cancellous bone, the upper andlower major side surfaces 68 and 70 of the wedge member 36 are slidingalong the portion of the outer layer 80 of hard cortical bone disposedbehind the thin leading edge 44 of the wedge member 36, that is, to theleft as viewed in FIGS. 5 and 6.

When the thin leading edge 44 of the wedge member 36 has moved rightward(as viewed in FIGS. 5 and 6) past the center of the bone 22, theopposite ends 52 and 54 or the thin leading edge again move intoengagement with the outer layer 80 of hard cortical bone. Continuedmovement of the wedge member 36 into the slot increases the extent ofengagement of the thin leading edge 44 of the wedge member with theouter layer 80 of hard cortical bone.

When the outer side surface 50 of the wedge member 36 has moved intoalignment with an outer side surface 94 (FIG. 6) on the lower portion 32of the bone 22, rightward (as viewed in FIG. 6) movement of the wedgemember is interrupted. At this time, the thin leading edge 44 of thewedge member is at the bottom of the saw slot formed in the bone 22.Opposite ends 52 and 54 of the thin leading edge 44 are disposed inengagement with the outer layer 80 of hard cortical bone. The mountingstrips 60, 62 and 64 are disposed in abutting engagement with the outerside surface 94 of the bone 22. Therefore, further rightward movement ofthe wedge member 36 into the slot is blocked and the wedge member is inthe position illustrated in FIGS. 5 and 6 relative to the bone 22.

During movement of the wedge member 36 into the slot in the bone 22, inthe manner previously described, the upper portion 30 of the bonepivoted relative to the lower portion 32 by force applied against theupper and lower portions of the bone by the wedge member 36. The upperend portion 30 of the bone 22 is pivoted relative to the lower portion32 of the bone about an axis extending parallel to the thin leading edge44 of the wedge member 36 and extending through the connector or hingeportion 40 of the bone 22.

When the outer side surface 50 on the wedge member 36 is moved intoalignment with the outer side surface 94 on the bone 22, the outer sidesurface 50 on the wedge member 36 will form a continuation of the outerside surface 94 of the bone 22. Although perfect alignment of the outerside surface 50 of the wedge member 36 with the outer side surface 94 ofthe bone is desired, there may be a slight misalignment or discontinuitywhere the outer side surface 50 of the wedge member 36 is aligned withthe outer side surface 94 of the bone 22.

In the embodiment of the wedge member 36 illustrated in FIGS. 3-6, thewedge member has been shown as being formed as a portion of a circlewith the thin edge 44 being a chord of the circle. However, it isbelieved that it will be preferred to form the wedge member 36 with aconfiguration which matches the configuration of the bone 22 in whichthe wedge member is to be inserted. Thus, it is contemplated that thebone 22 may have an irregular outer side surface 94 which is not formedas a portion of a circle. In such a situation, the outer side surface 50of the wedge member 36 would have a matching irregular configuration andwould not be formed as a portion of a cylinder.

By having the outer side surface 50 of the wedge member 36 have aconfiguration which is the same as the configuration as the outersurface 94 of the bone 22, almost perfect alignment can be obtainedbetween the wedge member 36 and the bone 22. Although there may be somemisalignment of the wedge member 36 and outer side surface 94 of thebone 22, the outer layer 80 of hard cortical bone is disposed inengagement with the upper and lower major side surfaces 68 and 70 of thewedge member 36 adjacent to the outer side surface 50 of the wedgemember throughout the extent of the outer side surface of the wedgemember.

By providing for engagement of the outer layer 80 of hard cortical bonewith the wedge member 36 throughout the extent of the opening to theslot which was formed in the bone 22, the area for transmittal of forcebetween the upper and lower major side surfaces 68 and 70 (FIG. 5) ofthe wedge member and the outer layer 80 of hard cortical bone ismaximized. This is because the entire extent of the outer layer 80 ofcortical bone which has been cut to form the slot is disposed inengagement with the wedge member 36. The only portion of the outer layer80 of hard cortical bone which does not engage the wedge member 36 isthe portion of the outer layer of hard cortical bone which is disposedin the connector or hinge portion 40 of the tibia bone 22 (FIGS. 5 and6). Therefore, there is no open space between surfaces on the outerlayer 80 of hard cortical bone where the slot was formed. This minimizesany tendency for stress concentrations to occur due to insertion of thewedge member 36 into the bone 22.

As was previously indicated, it is desired to have almost perfectalignment of the outer side surface 50 of the wedge member 36 with theouter side 94 of the bone 22. However, the obtaining of perfectalignment of the outer side surface 50 and is the wedge member 36 withthe outer side surface 94 on the bone 22 will be difficult due to thefact that bones on different patients do not have exactly the sameconfiguration. In addition, the obtaining of perfect alignment betweenthe outer side surface 50 of the wedge member 36 and the outer sidesurface 94 of the bone 22 is made difficult due to the fact that theconfiguration of the outer side surface 94 of the bone 22 varies alongthe extent of the bone.

The outer side surface 50 of the wedge member 36 is considered as beingaligned with the outer side surface 94 of the bone 22 when there is aslight discontinuity between the outer side surface 94 of the bone andthe outer side surface 50 of the wedge member 36. However, the extent ofthis discontinuity should be minimized. Close alignment of the outerside surface 50 of the wedge member 36 with the surface 94 on the bone22 maximizes the extent of engagement of the outer layer 80 of hardcortical bone with the wedge member. In addition, close alignment of theouter side surface 50 of the wedge member 36 with the surface 94 on thebone 22 minimizes the extent to which the wedge member projects outwardfrom the outer side surface of the bone.

Once the wedge member 36 has been positioned relative to the bone 22, inthe manner previously explained, the screws 58 are used to fixedlyconnect the wedge member 36 with the upper end portion 30 and lowerportion 32 of the bone 22. The screws 58 engage the outer layer of hardcortical bone (FIG. 5) to hold the wedge member 36 against movementrelative to the borne 22. It is contemplated that the wedge member 36could be connected with the bone 22 in a manner other than by usingscrews 58.

Since the wedge member 36 is rigid, it can immediately transmit loadsbetween the upper end portion 30 and lower portion 32 of the tibia bone22. Therefore, after the incision which exposed the site at which thewedge member 36 is inserted into the bone 22 has been closed, thepatient can begin to apply weight to the leg 20. This weight will betransmitted through the entire extent of the outer layer 80 of hardcortical bone. Thus, the portion of the outer layer 80 of hard corticalbone in the connector or hinge portion 40 of the tibia bone 22 is notsevered and can transmit force in the usual manner. The portion of theouter layer 80 of hard cortical bone which was cut to form the slot intowhich the wedge 36 was inserted, engages the upper and lower major sidesurfaces 68 and 70 of the wedge member 36. Since the wedge member 36 isrigid, force can be transmitted between the portions of the outer layer80 of hard cortical bone which engage the wedge member.

The central portion of the wedge member 36 engages the core 90 of softcancellous bone. Since the wedge member 36 is porous, the softcancellous bone can grow through openings formed in the wedge member 36to fuse the upper end portion 30 and lower portion 32 of the bone 22.The growth of the soft cancellous bone through the wedge member 36 maybe promoted by coating the wedge member with known bone growth inducingsubstances. In addition, it is believed that the hard cortical bone ofthe outer layer 80 will eventually grow through openings 74 in the wedgemember 36. The openings 74, which extend through the wedge member 36,may have a straight cylindrical configuration or may have an irregularconfiguration, similar to the configuration of openings or cavitiesformed in natural coral.

In the illustrations of FIGS. 5 and 6, the wedge member 36 is positionedin bone 22 at a location where an outer layer 80 of hard cortical boneextends around a core 90 of soft cancellous bone. However, the wedgemember 36 could be used at locations where one or both major sidesurfaces 68 and 70 are engaged by only hard cortical bone. Although thewedge member 36 has been illustrated in FIG. 2 being used in a bone 22in a patient's leg 20, the wedge member could be used with other bones.For example, the wedge member 36 could be used in association with bonesin a patient's arm, wrist, hand, ankle or foot.

In the embodiment of the invention illustrated in FIGS. 2-6, theopenings 74 a are provided in the wedge member 36 a to enable bone togrow through the wedge member. If desired, the openings 74 a could beomitted.

Wedge Member—Second Embodiment

In the embodiment of the wedge member 36 illustrated in FIGS. 2-6, thewedge member is pushed into a slot formed in the bone 22 by theapplication of force against the thick edge 46 of the wedge member. Inthe embodiment of the invention illustrated in FIGS. 7 and 8, a longthin screw member is utilized to guide at least a portion of themovement of the wedge member into the bone and to apply force to thewedge member to pull the wedge member into the slot formed in the bone.Since the embodiment of the invention illustrated in FIGS. 7 and 8 isgenerally similar to the embodiment of the invention illustrated inFIGS. 2-6, similar numerals will be utilized to designate similarcomponents, the suffix letter “a” being associated with the numerals ofFIGS. 7 and 8 to avoid confusion.

A wedge member 36 a is inserted into a bone 22 a to change the spatialrelationship of an upper portion 30 a (FIG. 7) of the bone relative to alower portion 32 a of the bone. The wedge member 36 a has a thin edge 44a and a thick edge 46 a. An outer side surface 50 a (FIG. 8) extendsbetween opposite ends 52 a and 54 a of the thin edge 44 a (FIG. 8).Upper and lower major side surfaces 68 a and 70 a (FIG. 7) extendbetween the thin edge 44 a and the thick edge 46 a. The flat upper andlower major side surfaces 68 a and 70 a are skewed at an acute anglerelative to each other.

Openings 74 a (FIG. 8) extend through the wedge member 36 a to enablebone to grow through the wedge member. The opening 74 a may have astraight cylindrical configuration or may have an irregularconfiguration, similar to openings formed in natural coral. The wedgemember 36 a may be coated with bone growth promoting material and/or theopenings 74 a filled with bone growth promoting material. If desired,the openings 74 a may be omitted.

A plurality of mounting strips 60 a, 62 a and 64 a (FIG. 8) engage anouter side surface 94 a of the bone 22 a. Suitable fasteners 58 aconnect the wedge member 36 a with the bone 22 a. The outer side surface50 a or the wedge member 36 a is aligned with the outer side surface 94a of the bone 22 a.

The wedge member 36 a has the same general construction as the wedgemember 36 of FIGS. 1-6. The wedge member 36 a is inserted into a slotformed in the bone 22 a in much the same manner as previously describedin connection with the embodiment of the invention illustrated in FIGS.1-6. However, in accordance with a feature of the embodiment of theinvention illustrated in FIGS. 7 and 8, a screw member 100 is utilizedto guide movement of the wedge member 36 a relative to the bone 22 a andto apply force to the wedge member 36 a to pull the wedge member into aslot formed in the bone 22 a.

The screw member 100 has a straight elongated shank 102 (FIG. 7) whichextends through the wedge member 36 a. A head end portion 104 of thescrew member 100 is fixedly connected with the shank 102 and disposed ina suitable recess formed in the wedge member 36 a. An opening 106 isformed in the mounting strip 62 a to provide access to the head endportion 104 of the screw member 100.

The screw member 100 has en externally threaded end portion 110 disposedon the end of the shank 102 opposite from the head end portion 104. Theexternally threaded end 110 of the screw member 100 is engageable withthe outer layer 80 a of hard cortical bone at the hinge or connectorsection 40 a of the bone 22 a.

When the wedge member 36 a is to be inserted into a slot in the bone 22a, the wedge member 36 a is moved into the slot in the manner previouslyexplained in conjunction with the embodiment of the inventionillustrated in FIGS. 2-6. As the wedge member 36 a approaches theposition shown in FIG. 7, the externally threaded end 110 of the screwmember 100 engages an inner side surface 114 of the outer layer 80 a ofhard cortical bone. The head end portion 104 of the screw member 100 isthen rotated. This causes the externally threaded end portion 110 of thescrew member to move into threaded engagement with the outer layer 80 aof hard cortical bone.

Continued rotation of the screw member 100 results in the head endportion 104 applying force against the wedge member 36 a to pull thewedge member toward the right (as viewed in FIG. 7). As the wedge member36 a is pulled toward the right by force transmitted from the screwmember 100 to the wedge member, the mounting strips 60 a, 62 a and 64 a(FIG. 8) move into abutting engagement with the outer side surface 94 aon the bone 22 a. The shank 102 of the screw member 100 guides movementof the wedge member 36 a relative to the bone 22 a. Rotation of thescrew member 100 and movement of the wedge member 36 a toward the right(as viewed in FIG. 7) is then interrupted. The mounting strips 60 a, 62a, and 64 a are fixedly connected with the upper end portion 30 a andlower portion 32 a of the bone 22 a by fasteners (screws) 58 a.

Although the wedge member 36 a has been illustrated in FIGS. 7 and 8 ata location where a layer 80 a of hard cortical bone encloses a core 90 aof soft cancellous bone, the wedge member 36 a could be used at alocation where the wedge member engages only hard cortical bone.Although it is preferred to provide the openings 74 a to enable bone togrow through the wedge member 36 a, the openings may be omitted ifdesired.

Wedge Member—Third Embodiment

In the embodiment of the wedge member illustrated in FIGS. 2-8, thewedge member has flat major side surfaces which extend from a relativelythick edge 46 of the wedge member to a relatively thin edge 44 of thewedge member. In the embodiment of the invention illustrated in FIG. 9,the wedge member is formed as an axially tapered screw. Since the wedgemember of the embodiment of the invention illustrated in FIG. 9 changesthe spatial relationship between end portions of a bone in a patient'sbody in a manner similar to that explained in conjunction with theembodiments of the invention illustrated in FIGS. 2-7, similar numeralswill be utilized to identify components of the embodiment of theinvention illustrated in FIG. 9, the suffix letter “b” being associatedwith the numerals of FIG. 9 to avoid confusion.

A wedge member 36 b has a thin edge or point 44 b and a thick edge orhead 46 b (FIG. 9). A mounting strip 62 b is connected with the thickedge 46 b and engages an outer side surface of a bone to limit movementof the wedge member 36 b relative to the bone. A side surface 50 b onthe thick edge 46 b of the wedge member 36 b is aligned with an outerside surface of the bone when the mounting strip 62 b engages the outerside surface of the bone.

In accordance with a feature of this embodiment of the invention, thewedge member 36 b has a spiral external thread convolution 116. Thethread convolution 116 has a generally conical configuration and tapersfrom the thick edge 50 b of the wedge member 36 b to the thin edge orpoint 44 b of the wedge member 36 b.

When the wedge member 36 b is to be inserted into a bone, a slot isformed in the bone in the same manner as previously explained inconjunction with the embodiment of the invention illustrated in FIGS.2-8. The wedge member 36 b is then screwed into the slot. In order toscrew the wedge member 36 b into the slot, force may be applied to themounting strip 62 b to rotate the wedge member 36 b about itslongitudinal central axis. Alternatively, a socket may be provided inthe thick edge 46 b to receive a suitable tool which transmits torque tothe wedge member 36 b.

As this occurs, the external thread convolution 116 on the wedge member36 b cooperates with the hard cancellous outer layer of the bone toeffect axial movement of the wedge member into the slot in the bone. Asthe wedge member 36 b enters the slot in the bone, the portion of thebone, corresponding to the upper end portion 30 of FIG. 2, pivotsrelative to a lower portion 32. This results in a change in the spatialrelationship between the upper portion and lower portion of the bone.

Prior to moving the wedge member 36 b into the slot in the bone, alongitudinal central axis of the wedge member is aligned with an axiswhich is perpendicular to a bottom of the slot and extends through thecenter of the bone. The wedge member 36 b is then rotated about itslongitudinal central axis. As the wedge member 36 b rotates and movesinto the slot, the wedge member moves along a straight path whichextends perpendicular to an axis about which the upper end portion ofthe bone is pivoted relative to the lower portion of the bone. Movementof the wedge member 36 b into the slot is interrupted with the thin edgeor point 44 b spaced from a connector or hinge portion of the bone whichinterconnects the upper end portion and lower portion of the bone.

A plurality of openings 74 b are formed in the wedge member 36 b toenable bone to grow through the wedge member in the manner previouslyexplained in conjunction with the embodiment of FIGS. 1-8. The wedgemember 36 b is coated with a bone growth promoting material. The wedgemember 36 b may be hollow to provide a cavity to hold bone growthpromoting material.

Wedge Member—Fourth Embodiment

An the embodiment of the invention illustrated in FIGS. 2-9, the wedgemember has openings to enable bone to grow through the wedge member. Inthe embodiment of the invention illustrated in FIG. 10, the wedge memberis hollow to provide a cavity which holds bone growth promotingmaterial. Since the embodiment of the invention illustrated in FIG. 10is generally similar to the embodiment of the invention illustrated inFIGS. 2-9, similar numerals will be utilized to designate similarcomponents, the suffix letter “c” being associated with the embodimentof FIG. 10 to avoid confusion.

A wedge member 36 c (FIG. 10) has a thin edge 44 c and a thick edge 46c. An outer side surface 50 c extends between opposite ends of the thinedge 44 c in the same manner as is illustrated in FIGS. 3 and 6 for theembodiment of the invention of FIGS. 2-6. The wedge member 36 c has thesame overall configuration as the wedge member 36 of FIGS. 2-6.

A mounting strip 62 c is connected with the thick edge 44 c of the wedgemember 36 c. Additional mounting strips, corresponding to the mountingstrips 60 and 64 of the embodiment of the invention illustrated in FIGS.3 and 6, are provided on the wedge member 36 c. When the outer sidesurface 50 c on the wedge member 36 c has moved into alignment with theouter side surface of the bone, the mounting strip 62 c engages theouter side surface of the bone. Suitable fasteners may be used tointerconnect the bone and the mounting strip 62 c. Although only asingle mounting strip 62 c has been illustrated in FIG. 10, it should beunderstood that additional mounting strips, corresponding to themounting strips 62 and 64 of FIG. 3, are associated with the wedgemember 36 c.

The wedge member 36 c has a flat upper major side surface 68 c and aflat lower major side surface 70 c. The upper and lower major sidesurfaces 68 c and 70 c have the same configuration as the upper andlower major side surfaces 68 and 70 of the embodiment of the inventionillustrated in FIGS. 2-6. The outer side surface 50 c has the sameconfiguration as the outer side surface 50 of the embodiment of theinvention illustrated in FIGS. 2-6. The upper and lower major sidesurfaces 68 c and 70 c (FIG. 10) are disposed at an acute angle andtaper from the thick edge 46 c to the thin edge 44 c of the wedge member36 c.

The wedge member 36 c is rigid to enable it to be weight bearing as soonas it is positioned in a bone. Although the wedge member 36 c could beformed of many different materials, it is formed of stainless steel.

In accordance with a feature of this embodiment of the invention, thewedge member 36 c (FIG. 10) is hollow. Therefore, a compartment orcavity 120 is formed in the wedge member 36 c. The compartment 120 hasupper and lower inner side surfaces 122 and 124 which are smaller thanthe upper and lower major side surfaces 68 c and 70 c of the wedgemember 36 c. However, the inner side surfaces 122 and 124 of thecompartment 120 have the same general configuration as the upper andlower major side surfaces 68 c and 70 c of the wedge member 36 c.

The compartment 120 is filled with a bone growth inducing material 130.The bone growth inducing material 130 is (not shown) formed in eitherthe upper major side surface 68 c or the lower major side surface 70 cof the wedge member 36 c. Once the compartment 120 has been filled withthe bone growth inducing material 130, the opening to the compartment isclosed. However, openings 74 c in the wedge member 36 c enable bone togrow through the wedge member.

The growth of bone through the wedge member 36 c is promoted by the bonegrowth inducing material 130 in the compartment 120. The bone growthinducing material 130 in the compartment 120 may be any one of manyknown compositions. For example, apatite compositions with collagen maybe utilized. Demineralized bone powder may also be utilized. Regardlessof which of the known bone growth inducing materials are selected, thepresence of the bone growth inducing material in the compartment 120will promote a growth of bone through the openings 74 c in the wedgemember 36 c.

The wedge member 36 c may, itself, be formed of a suitable rigidmaterial, such as tantalum or stainless steel. In addition to the bonegrowth inducing material 130 in the compartment 120, the surfaces of thewedge member 36 c and the openings 74 c may be coated with suitable bonegrowth inducing materials. Although the wedge member 36 c has been shownas having straight cylindrical openings 74 c through which bone grows,the wedge member 360 could have an open celled construction if desired.

Wedge Member—Fifth Embodiment

In the embodiment of the invention illustrated in FIGS. 2-10, aplurality of relatively small openings 74 extend through the variouswedge members to enable bone to grow through the wedge members. In theembodiment of the invention illustrated in FIGS. 11 and 12, a relativelylarge central opening is provided in the wedge member to enable bone togrow through the wedge member. Since the embodiment of the inventionillustrated in FIGS. 11 and 12 is generally similar to the embodiment ofthe invention illustrated in FIGS. 2-10, similar numerals will beutilized to designate similar components, the suffix letter “d” beingassociated with the numerals of FIGS. 11 and 12 to avoid confusion.

A wedge member 36 d (FIGS. 11 and 12) has a thin edge 44 d and a thickedge 46 d. An outer side surface 50 d extends between opposite ends 52 dand 54 d (FIG. 12) of the thin edge 44 d. The outer side surface 50 dhas a configuration which corresponds to the configuration of an outerside surface 94 d of a bone 22 d (FIG. 11). The wedge member 36 d hasflat upper and lower major side surfaces 68 d and 70 d which are skewedat an acute angle relative to each other and extend between the thinedge 44 d and the thick edge 46 d of the wedge member 36 d.

The wedge member 36 d has the same overall configuration as the wedgemember 36 of the embodiment of the invention illustrated in FIGS. 2-6.Thus, the side surface 50 d (FIG. 12) has the same configuration as theside surface 50 of FIGS. 3 and 4. The upper and lower major sidesurfaces 68 d and 70 d (FIGS. 11 and 12) have outer edge portions withthe same configuration as the outer edge portion of the major sidesurfaces 68 and 70 of FIGS. 3 and 4.

When the wedge member 36 d has been inserted into a slot formed in abone in the manner previously explained in conjunction with theembodiment of the invention illustrated in FIGS. 2-6, mounting strips 60d, 62 d, and 64 d on the wedge member 36 d move into abutting engagementwith the outer side surface 94 d of the bone 22 d (FIG. 17). Themounting strips 60 d, 62 d, and 64 d are fixedly connected with theupper end portion 30 d and lower portion 32 d of the bone 22 d bysuitable fasteners 58 d. The fasteners 58 d retain the wedge member 36 dagainst movement from a position in which the side surface 50 d isaligned with the outer side surface 94 d of the bone 22 d.

As the wedge member 36 d is inserted into the slot in the bone 22 d, anupper portion 30 d (FIG. 11) of the bone 22 d is pivoted relative to alower portion 32 d to change the spatial relationship between the upperportion 30 d and lower portion 32 d of the bone 22 d. The upper portion30 d of the bone 22 d pivots about an axis which extends parallel to thethin edge 44 d of the wedge member 36 d. The axis about which the upperportion 30 d of the bone pivots extends through the hinge or connectorportion 40 d of the bone 22 d and is parallel to the bottom of the slotformed in the bone 22 d to receive the wedge member 36 d.

In accordance with a feature of the present invention, the wedge member36 d has a large central opening 134 through which bone may grow. Theopenings 134 extends between upper and lower major side surfaces 68 dand 70 d of the wedge member 36 d. The opening 134 is configured in sucha manner that the upper and lower major side surfaces 68 d and 70 d ofthe wedge member 36 d engage an outer layer 80 d of hard cortical bonethroughout movement of the wedge member 36 d into the slot formed in thebone 22 d.

When the wedge member 36 d has moved into the bone 22 d, to the positionshown in FIGS. 11 and 12, the large opening 134 enables the core 90 d ofsoft cancellous bone to easily grow through the wedge member 36 d. Ifdesired, material 130 d (FIG. 11) for promoting a growth of bone couldbe positioned in the opening 134. At this time, the outer layer 80 d ofhard cortical bone is disposed in abutting engagement with oppositemajor side surfaces 68 d and 70 d on the wedge member 36 d throughoutthe extent of the opening to the slot into which the wedge member isinserted. Relatively small openings 74 d are provided in the wedgemember 36 d to enable hard cortical bone to grow through the wedgemember.

The opening 134 has a configuration which is similar to but smaller thanthe overall configuration of the wedge member 36 d. Thus, the opening134 has a flat, rectangular side surface 136 which extends parallel tothe thin edge 44 d of the wedge member 36 d. The opening 134 has anarcuate side surface 138 which is spaced substantially the same distancefrom the outer side surface 50 d throughout the extent of the sidesurface 138 of the opening 134 and the side surface 50 d of the wedgemember 36 d.

The side surface 138 of the opening 134 is spaced from the outer sidesurface 50 d by a distance which is greater than the thickness of theouter layer 80 d of hard cortical bone. Therefore, as the wedge member36 d is inserted into the slot formed in the bone 22 d, the outer layer80 d of hard cortical bone engages the upper and lower major sidesurfaces 58 d and 70 d of the wedge member 36 d. The outer layer 80 d ofhard cortical bone is in engagement with the upper and lower major sidesurfaces 68 d and 70 d of the wedge member 36 d when the outer sidesurface 50 d of the wedge member is aligned with the outer side surface94 d of the bone 22 d. The outer layer 80 d of hard cortical bone isdisposed in engagement with the wedge member 36 d throughout the extentof the opening to the slot into which the wedge member 36 d is inserted.

When the wedge member 36 d has been moved into the slot formed in thebone 20 d, the mounting strips 60 d, 62 d and 64 d move into abuttingengagement with the outer side surface 94 d of the bone. Suitablefasteners 58 d can then be utilized to connect the wedge member 36 dwith the upper end portion 30 d and the lower portion 32 d of the bone22 d. The fasteners 58 d maintain the outer side surface 50 d on thewedge member 36 d in alignment with the outer side surface 94 d of thebone 22 d.

The wedge member 36 d can, upon being positioned relative to the boneand an incision which was made to expose the bone closed, be loadbearing. This is because the outer layer 80 d of hard cortical boneextends through the hinge portion 40 d and can support a load in theusual manner. The outer layer 80 d of hard cortical bone is disposed inengagement with the upper and lower major side surfaces 68 d and 70 d ofthe rigid wedge member 36 d at a location offset to the left (as viewedin FIG. 12) from the hinge on connector portion 40 d. Therefore, forcecan be transmitted between the upper end portion 30 d and lower portion32 d (FIG. 11) through the wedge member 36 d as soon as the wedge memberhas been properly installed in the bone 22 d.

With the passage of time, the soft cancellous bone 90 d grows throughand completely fills the opening 134 in the wedge member 36 d. Althoughone specific opening configuration has been illustrated in FIG. 12, itis contemplated that the opening 134 could have any desiredconfiguration. In addition to the bone growth promoting material 130 d,the wedge member 36 d could be coated with bone growth promotingmaterial. If desired, the small openings 74 d could be omitted.

Wedge Member—Fifth Embodiment

In the embodiment of the invention illustrated in FIGS. 1-6, the wedgemember has flat major side surfaces. In the embodiment of the inventionillustrated in FIGS. 13 and 14, the wedge member has major side surfaceswith a stepped configuration. Since the embodiment of the inventionillustrated in FIGS. 13 and 14 is generally similar to the embodiment ofthe invention illustrated in FIGS. 2-6, similar numerals will beutilized to identify similar components, the suffix letter “e” beingassociated with the numerals of FIGS. 13 and 14 to avoid confusion.

A wedge member 36 e is used to change a spatial relationship between anupper end portion 30 e and a lower portion 32 e of a bone 22 e (FIG.13). The wedge member 36 e includes a thin edge 44 e and a thick edge 46e. The wedge member 36 e has an outer side surface 50 e which extendsbetween opposite ends 52 e and 54 e (FIG. 14) of the thin edge 44 e. Thewedge member 36 e has an upper major side 68 e (FIG. 13) and a lowermajor side 70 e.

A plurality of mounting strips 60 e, 62 e and 64 e move into abuttingengagement with an outer side surface 94 e of the bone 22 e when thewedge member 36 e is inserted into a slot formed in the bone in themanner previously explained. As the wedge member 36 e is inserted in tothe slot in the bone, the upper end portion 30 e of the bone 22 e pivotsabout an axis which extends through a connector or hinge portion 40 e ofthe bone. The axis about which the upper portion 30 e of the bone pivotsextends parallel to the thin edge 44 e of the wedge member 36 e.

When the mounting strips 60 e, 62 e and 64 e have moved into abuttingengagement with the outer side surface 94 e of the bone 22 e, the outerside surface 50 e is in alignment with the outer side surface 94 e ofthe bone 22 e. Suitable fasteners 58 e are utilized to connect the wedgemember 46 e with the upper end portion 30 e and lower portion 32 e ofthe bone 22 e in the manner previously explained.

In accordance with a feature of this embodiment of the invention, theupper major side 68 e of the wedge member 36 e has a steppedconfiguration. Thus, the upper major side 68 e of the wedge member 36 eincludes a flat surface area 150 (FIGS. 13 and 14) which extends at afirst, relatively small acute angle relative to the lower major sidesurface 70 e of the wedge member 36 e. A second surface area 152 extendsfrom the surface area 150 toward the outer side surface 50 e of thewedge member 36 e at a second acute angle relative to the lower sidesurface 70 e. The second acute angle, at which the side surface 152extends relative to the lower side surface 70 e (FIG. 13), is greaterthan the first angle at which the side surface area 150 extends relativeto the lower side surface 70 e.

Finally, the wedge member 36 e includes a surface area 154 which extendsoutward from the surface area 152 to the outer side surface 50 e of thewedge member 36 e. The surface 154 slopes at an acute angle relative tothe lower side surface 70 e of the wedge member 36 e. The angle whichthe surface 154 makes with the dower side surface 70 e is greater thanthe angle which the surface area 150 makes with the lower side surface70 e. The angle which the surface area 150 makes with the lower sidesurface 70 e of the wedge member 36 e is less than the angle which thesurface area 152 makes with the lower side surface 70 e (FIG. 13).

The surface area 154 extends a substantially constant distance from theouter side surface 50 e of the wedge member 36 e throughout the extentof the surface area 154 (FIG. 14). Since the surface area 152 extendsbetween the surface area 150 and the surface area 154 (FIG. 14) theextent of the surface area 152 varies as a function of the distance ofthe surface area from a perpendicular to the thin edge 44 e and throughthe center of wedge member 36 e. The resulting stepped configuration ofthe wedge member 36 e facilitates initial movement of the wedge memberinto the slot formed in the bone 22 e.

A plurality of openings 74 e extend through the wedge member 36 e. Theopenings 74 e enable bone to grow through the wedge member 36 e. Theopenings 74 e may have a straight cylindrical configuration or may havean open-celled structure. The wedge member 36 e may be coated with bonegrowth promoting material and/or the openings 74 e may be at leastpartially filled with bone growth promoting material.

An outer layer 80 e of hard cortical bone is disposed in engagement withthe surface area 154 adjacent to the outer side surface 50 e of thewedge member 36 e. The portion of the outer layer 80 e of hard corticalbone exposed by formation of the slot in the bone also engages the lowermajor side surface 70 e of the wedge member 36 e. The wedge member 36 eis formed of a rigid material which is capable of transmitting forcebetween the upper end portion 30 e and the lower portion 32 e of thebone 22 e. Therefore, the bone is immediately weight supporting when thewedge member 36 e is positioned in the bone in the manner illustrated inFIGS. 13 and 14.

CONCLUSION

In view of the foregoing description, it is apparent that the presentinvention provides a new and improved method and apparatus for use inchanging a spatial relationship between portions of a bone 22 in apatient's body. When this is to be done, an opening is formed in aportion of the patient's body tissue to at least partially expose thebone 22. Force is applied to the bone 22 with a wedge member 36 to moveone portion 30 of the bone relative to another portion 32 of the bone.The wedge member 36 may be fixedly connected with either or bothportions of the bone. The opening in the patient's body is then closedwith the wedge member 36 disposed in engagement with the bone 22. Forcecan be transmitted between portions 30 and 32 of the bone 22 through thewedge member 36.

The wedge member 36 may taper from a thick edge 46 to a thin edge 44 andhave a side surface 50 which extends from one end 52 of the thin edge,along the thick edge, to the opposite end 54 of the thin edge. The sidesurface 50 of the wedge member 36 has a cross sectional configurationcorresponding to the configuration of a portion of an outer side surface94 of the bone 22. This enables the wedge member 36 to be aligned withthe outer side surface 94 of the bone 22.

The wedge member 36 may be positioned relative to the bone 22 at alocation where a layer 80 of hard cortical bone encloses soft cancellousbone 90. Opposite ends 52 and 54 of the thin edge 44 of the wedge member36 may be positioned in engagement with the hard cortical bone 80 whilea central portion of the thin edge 44 of the wedge member 36 engages thesoft cancellous bone. In addition, the layer 80 of hard cortical bonemay engage the wedge member 36 adjacent to the side surface 50 of thewedge member.

It is contemplated that the wedge member 36 may have many differentconstructions. It is believed that it will be advantageous to form thewedge member 36 with one or more openings 74 through which bone cangrow. The wedge member 36 may be hollow and contain material 130 whichpromotes the growth of bone through the wedge member.

A screw member 100 may extend ahead of the thin leading edge 44 of thewedge member 36 and engage hard cortical bone. Force may be transmittedfrom the screw member 100 to the wedge member 36 to move the wedgemember relative to the bone. Alternatively, the wedge member 36 may havea circular cross sectional configuration with an external threadconvolution 116 to enable the wedge member to be moved into an openingin a bone by rotating the wedge member.

What is claimed is:
 1. An implantable device for maintaining a spatialrelationship between first and second bone surfaces, the devicecomprising: a support body configured to be positioned into at least aportion of a space located between the first and second bone surfaces,the support body includes a longitudinal central axis, an upper surface,a lower surface, a trailing end, a first side, a second side and aleading end, the upper surface defining an upper plane, the leading endextending generally linearly between a first end and a second end, arecess extending into the support body from the trailing end proximatethe longitudinal central axis; and a mounting strip including anopening, a leading side and a trailing side, the opening aligned withthe recess along longitudinal axes of the opening and the recess whenthe mounting strip is connected to the trailing end of the support bodywith the leading side facing the support body, the opening and therecess configured to receive a screw member such that a shank of thescrew member extends through the upper plane when the shank ispositioned in the recess, a countersink formed at least partially in thesupport body and configured to receive a head portion of the screwmember such that the head portion is positioned between a trailing endplane defined by the trailing side of the mounting strip and the leadingend when the screw member is received in the opening and the recess. 2.An implantable device as set forth in claim 1 wherein the mounting stripis in engagement with cortical bone when the support body is between thefirst and second bone portions and the support body is in engagementwith cancellous bone when the support body is between the first andsecond bone surfaces.
 3. An implantable device for maintaining a spatialrelationship between first and second bone surfaces, the devicecomprising: a support body including a longitudinal central axis, anupper surface, a lower surface, a trailing end, a first side, a secondside and a leading end, the upper surface defining an upper plane, theleading end extending generally linearly between a first end and asecond end, a horizontal body plane defined on the longitudinal centralaxis, a recess extending into the support body from the trailing endtoward the leading end and located at least partially on the horizontalbody plane, the support body constructed of a polymeric material; and amounting strip including an opening, a leading side and a trailing side,the opening aligned with the recess along longitudinal axes of theopening and the recess when the mounting strip is connected to thetrailing end of the support body with the leading side facing thesupport body, the opening and the recess configured to receive a screwmember such that a shank of the screw member extends through the upperplane when the shank is positioned in the recess, a countersink formedat least partially in the support body and configured to receive a headportion of the screw member such that the head portion is positionedbetween a trailing end plane defined by the trailing side of themounting strip and the leading end when the screw member is received inthe opening and the recess, the mounting strip constructed of a metallicmaterial.
 4. The implantable device as set forth in claim 1, wherein therecess extends generally linearly from the trailing end to the uppersurface.
 5. The implantable device as set forth in claim 1, wherein therecess extends generally linearly from the trailing end toward the uppersurface.
 6. The implantable device as set forth in claim 1, wherein thesupport body includes a bone growth opening therethrough, the bonegrowth opening configured to enable bone to grow through the supportbody.
 7. The implantable device as set forth in claim 6, wherein thebone growth opening has a generally straight, cylindrical configuration.8. The implantable device as set forth in claim 6, wherein the bonegrowth opening is comprised of a plurality of bone growth openings. 9.The implantable device as set forth in claim 1, wherein the support bodyhas a generally frusta-circular shape when viewed toward the uppersurface, the first side, the second side and the trailing end beingarcuate.
 10. The implantable device as set forth in claim 1, wherein themounting strip is comprised of a first mounting strip, a second mountingstrip, and a third mounting strip.
 11. The implantable device as setforth in claim 1, wherein the support body has an open celledconstruction.
 12. The implantable device as set forth in claim 1,wherein the lower surface defines a lower plane, the upper plane taperstoward the lower plane from the trailing end toward the leading end. 13.The implantable device as set forth in claim 12, wherein the upper planeand the lower plane define an acute angle, the acute angle being lessthan twenty degrees (20°).
 14. The implantable device as set forth inclaim 13, wherein the acute angle is within a range between one andtwenty degrees (1-20°).
 15. The implantable device as set forth in claim14, wherein the acute angle is between two and ten degrees (2-10°). 16.The implantable device as set forth in claim 1, wherein the support bodyis constructed of a material selected from the group consisting of humanbone, animal bone, a metallic material, a stainless steel material, atantalum material, a porous ceramic material and a polymeric material.17. The implantable device as set forth in claim 1, wherein the supportbody has the form of a portion of a circle with the leading end being achord of the circle when viewed toward the top surface.
 18. Theimplantable device as set forth in claim 1, wherein the mounting stripis comprised of a metallic material and the support body is constructedof a polymeric material.
 19. The implantable device as set forth inclaim 1, further comprising: first and second fasteners, the mountingstrip including an upper portion extending above the upper surface and alower portion extending below the lower surface when the mounting stripis connected to the trailing end of the support body, the first fastenerconfigured to extend through the upper portion and the second fastenerconfigured to extend through the lower portion and into the bone tosecure the mounting strip to the bone.
 20. The implantable device as setforth in claim 3, wherein the recess extends generally linearly from thetrailing end toward the upper surface.
 21. The implantable device as setforth in claim 3, wherein the support body includes a bone growthopening therethrough, the bone growth opening configured to enable boneto grow through the support body.
 22. The implantable device as setforth in claim 21, wherein the bone growth opening has a generallystraight, cylindrical configuration.
 23. The implantable device as setforth in claim 21, wherein the bone growth opening is comprised of aplurality of bone growth openings.
 24. The implantable device as setforth in claim 3, wherein the support body has a generallyfrusta-circular shape when viewed toward the upper surface, the firstside, the second side and the trailing end being arcuate.
 25. Theimplantable device as set forth in claim 3, wherein the mounting stripis comprised of a first mounting strip, a second mounting strip, and athird mounting strip.
 26. The implantable device as set forth in claim3, wherein the support body has an open celled construction.
 27. Theimplantable device as set forth in claim 3, wherein the lower surfacedefines a lower plane, the upper plane tapers toward the lower planefrom the trailing end toward the leading end.
 28. The implantable deviceas set forth in claim 27, wherein the upper plane and the lower planedefine an acute angle, the acute angle being less than twenty degrees(20°).
 29. The implantable device as set forth in claim 28, wherein theacute angle is within a range between one and twenty degrees (1-20°).30. The implantable device as set forth in claim 29, wherein the acuteangle is between two and ten degrees (2-10°).
 31. The implantable deviceas set forth in claim 3, wherein the support body has the form of aportion of a circle with the leading end being a chord of the circlewhen viewed toward the top surface.
 32. The implantable device as setforth in claim 3, further comprising: first and second fasteners, themounting strip including an upper portion extending above the uppersurface and a lower portion extending below the lower surface when themounting strip is connected to the trailing end of the support body, thefirst fastener configured to extend through the upper portion and thesecond fastener configured to extend through the lower portion and intothe bone to secure the mounting strip to the bone.